Miscellaneous active electrical nonlinear devices – circuits – and – Specific identifiable device – circuit – or system – Unwanted signal suppression
Patent
1994-12-02
1997-04-08
Nelms, David C.
Miscellaneous active electrical nonlinear devices, circuits, and
Specific identifiable device, circuit, or system
Unwanted signal suppression
327553, 327530, 327532, 327538, 327541, 327379, 323313, H03K 500, H03K 1716
Patent
active
056191669
ABSTRACT:
An adaptive active filtering method and apparatus that detects changes in noise conditions and reduces the signal propagation speed as noise conditions worsen. This active filter has a level shifting inverter, which inverts the input signal and converts the logic levels of the input signal into chip logic levels. This inverted input signal is presented at the input of a driver inverter, which once again inverts the signal. This second inversion filters out input noise, because a voltage controlled device (which is attached to the driver inverter) reduces the switching speed of this inverter as the noise condition worsen; this reduction in switching speed reduces the propagation speed and thus filters out noise. In addition, two cascaded voltage generator circuits create a reference voltage generator, that enables the voltage controlled device to detect changes in noise conditions, by providing it with a reference voltage that varies in a controlled and specific manner with the changes in transistor conductance parameters, power supply voltages, and operating temperatures. This reference voltage generator controls the variance of the reference voltage in two manners. First, this generator utilizes a positive temperature coefficient floating voltage source to increase (in a controlled fashion) the variance of the reference voltage with changes in the temperature. Second, this generator uses a feedback path, between the first and the second voltage generator circuits, to compensate for uncontrolled variations of the reference voltage due to process variations in transistor conductance parameters.
REFERENCES:
patent: 4216388 (1980-08-01), Wilson
patent: 4473762 (1984-09-01), Iwahashi et al.
patent: 4723108 (1988-02-01), Murphy et al.
patent: 4769589 (1988-09-01), Rosenthal
patent: 4954769 (1990-09-01), Kalthoff
patent: 4972101 (1990-11-01), Partovi et al.
patent: 5208527 (1993-05-01), Poletto et al.
patent: 5212440 (1993-05-01), Waller
patent: 5245273 (1993-09-01), Greaves et al.
patent: 5252909 (1993-10-01), Aizaki
patent: 5399960 (1995-03-01), Gross
patent: 5424629 (1995-06-01), Fujiwara
Cypress Semiconductor Corporation
Nelms David C.
Phan Trong
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